There is an optical measurement system that makes the light from the light source enter in the optical sensor and receives output light based on the incident light therefrom, thereby acquiring information on a subject from the result. Such an optical measurement system includes, for example, an optical sensor chip and a measurement unit.
The optical sensor chip is capable of retaining a sample liquid and is configured to allow light to enter therein from and exit therefrom to the outside. Having entered inside the optical sensor chip, the light is affected by a component contained in the sample liquid retained therein and is output to the outside of the optical sensor chip. The measurement unit includes at least a light transceiver and a processor. The light transceiver generates light to be incident on the optical sensor chip and receives output light therefrom. The processor processes the received output light to acquire information on the component of the sample liquid.
As one example of the optical measurement system may be cited an optical waveguide measurement system. The optical waveguide measurement system includes an optical waveguide sensor chip (hereinafter sometimes simply referred to as “sensor chip”), as an optical sensor chip. The optical waveguide measurement system is capable of measuring, for example, the density of a test object contained in a sample liquid by using waveguiding effect.
The optical waveguide sensor chip includes an optical waveguide part and a functional layer formed in the boundary between the optical waveguide part and a sample liquid container. The light incident on the optical waveguide part is affected depending on the reaction of the functional layer to a component contained in the sample liquid. The affected light is received as output light.
The optical measurement system has an attachment part. In the optical waveguide measurement system, if the measurement unit performs a measurement while not equipped properly with an optical waveguide sensor chip, for example, the light transceiver receives abnormal light. Accordingly, the measurement results in an error. In a state where the measurement unit is not equipped properly with an optical waveguide sensor chip, for example, the optical waveguide sensor chip is mounted on the placement surface of the measurement unit with the bottom surface at a predetermined angle thereto. When a measurement is performed in this state, the angle of light incident on the optical waveguide part changes by degrees of the predetermined angle. If this happens, the light may not properly propagate in the optical waveguide part. Consequently, the light transceiver receives abnormal light, and the measurement results in an error. Examples of the abnormal light include scattered light, stray light, and the like.
That is, to properly mount the optical waveguide sensor chip on the measurement unit, at least the bottom surface of the optical waveguide sensor chip needs to be in parallel to the placement surface. For this reason, the operator is required to visually check whether the bottom surface is in parallel to the placement surface each time he/she mounts the optical waveguide sensor chip on the measurement unit. However, if a number of tests, such as tests for infection, are required, this work imposes a heavy burden on the operator. In addition, the check work prolongs the time necessary for the tests.